File:  [Qemu by Fabrice Bellard] / qemu / qemu-aio.h
Revision 1.1.1.3 (vendor branch): download - view: text, annotated - select for diffs
Tue Apr 24 17:34:04 2018 UTC (2 years, 2 months ago) by root
Branches: qemu, MAIN
CVS tags: qemu1001, qemu1000, qemu0151, qemu0150, qemu0141, qemu0140, qemu0130, qemu0125, qemu0124, qemu0123, qemu0122, qemu0121, qemu0120, HEAD
qemu 0.12.0

    1: /*
    2:  * QEMU aio implementation
    3:  *
    4:  * Copyright IBM, Corp. 2008
    5:  *
    6:  * Authors:
    7:  *  Anthony Liguori   <aliguori@us.ibm.com>
    8:  *
    9:  * This work is licensed under the terms of the GNU GPL, version 2.  See
   10:  * the COPYING file in the top-level directory.
   11:  *
   12:  */
   13: 
   14: #ifndef QEMU_AIO_H
   15: #define QEMU_AIO_H
   16: 
   17: #include "qemu-common.h"
   18: #include "qemu-char.h"
   19: 
   20: /* Returns 1 if there are still outstanding AIO requests; 0 otherwise */
   21: typedef int (AioFlushHandler)(void *opaque);
   22: 
   23: /* Runs all currently allowed AIO callbacks of completed requests in the
   24:  * respective AIO backend. Returns 0 if no requests was handled, non-zero
   25:  * if at least one queued request was handled. */
   26: typedef int (AioProcessQueue)(void *opaque);
   27: 
   28: /* Flush any pending AIO operation. This function will block until all
   29:  * outstanding AIO operations have been completed or cancelled. */
   30: void qemu_aio_flush(void);
   31: 
   32: /* Wait for a single AIO completion to occur.  This function will wait
   33:  * until a single AIO event has completed and it will ensure something
   34:  * has moved before returning. This can issue new pending aio as
   35:  * result of executing I/O completion or bh callbacks. */
   36: void qemu_aio_wait(void);
   37: 
   38: /*
   39:  * Runs all currently allowed AIO callbacks of completed requests. Returns 0
   40:  * if no requests were handled, non-zero if at least one request was
   41:  * processed.
   42:  */
   43: int qemu_aio_process_queue(void);
   44: 
   45: /* Register a file descriptor and associated callbacks.  Behaves very similarly
   46:  * to qemu_set_fd_handler2.  Unlike qemu_set_fd_handler2, these callbacks will
   47:  * be invoked when using either qemu_aio_wait() or qemu_aio_flush().
   48:  *
   49:  * Code that invokes AIO completion functions should rely on this function
   50:  * instead of qemu_set_fd_handler[2].
   51:  */
   52: int qemu_aio_set_fd_handler(int fd,
   53:                             IOHandler *io_read,
   54:                             IOHandler *io_write,
   55:                             AioFlushHandler *io_flush,
   56:                             AioProcessQueue *io_process_queue,
   57:                             void *opaque);
   58: 
   59: #endif

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